diff --git a/xpcom/base/CycleCollectedJSContext.cpp b/xpcom/base/CycleCollectedJSContext.cpp
index 90d5bf94abe3..18114b70ead0 100644
--- a/xpcom/base/CycleCollectedJSContext.cpp
+++ b/xpcom/base/CycleCollectedJSContext.cpp
@@ -1280,7 +1280,7 @@ CycleCollectedJSContext::JSObjectsTenured()
   for (auto iter = mNurseryObjects.Iter(); !iter.Done(); iter.Next()) {
     nsWrapperCache* cache = iter.Get();
     JSObject* wrapper = cache->GetWrapperPreserveColor();
-    MOZ_ASSERT(wrapper);
+    MOZ_DIAGNOSTIC_ASSERT(wrapper);
     if (!JS::ObjectIsTenured(wrapper)) {
       MOZ_ASSERT(!cache->PreservingWrapper());
       const JSClass* jsClass = js::GetObjectJSClass(wrapper);